diff --git a/toolchain/check/action.h b/toolchain/check/action.h
index 13048d138147..a8ef790fb2da 100644
--- a/toolchain/check/action.h
+++ b/toolchain/check/action.h
@@ -83,17 +83,26 @@ auto AddDependentActionSplice(Context& context, LocT loc, InstT inst,
 // to act as the type of the splice.
 template <typename ActionT, typename LocIdT>
 auto HandleAction(Context& context, LocIdT loc_id,
-                  SemIR::TypeInstId result_type_inst_id, ActionT action_inst)
-    -> SemIR::InstId {
+                  SemIR::TypeInstId expected_result_type_inst_id,
+                  ActionT action_inst) -> SemIR::InstId {
   CARBON_CHECK(action_inst.type_id == SemIR::InstType::TypeId);
   if (!ActionIsPerformable(context, action_inst)) {
     return AddDependentActionSplice(context,
                                     SemIR::LocIdAndInst::RuntimeVerified(
                                         context.sem_ir(), loc_id, action_inst),
-                                    result_type_inst_id);
+                                    expected_result_type_inst_id);
   }
 
-  return PerformAction(context, loc_id, action_inst);
+  auto expected_result_type_id =
+      expected_result_type_inst_id.has_value()
+          ? context.types().GetTypeIdForTypeInstId(expected_result_type_inst_id)
+          : SemIR::TypeId::None;
+  auto result_id = PerformAction(context, loc_id, action_inst);
+  auto result_type_id = context.insts().Get(result_id).type_id();
+  CARBON_CHECK(expected_result_type_id == SemIR::TypeId::None ||
+               result_type_id == SemIR::ErrorInst::TypeId ||
+               result_type_id == expected_result_type_id);
+  return result_id;
 }
 
 namespace Internal {
diff --git a/toolchain/check/function.cpp b/toolchain/check/function.cpp
index c601f5b73734..9cc135755200 100644
--- a/toolchain/check/function.cpp
+++ b/toolchain/check/function.cpp
@@ -45,8 +45,9 @@ auto FindSelfPattern(Context& context,
 auto AddReturnPattern(Context& context, SemIR::LocId loc_id,
                       Context::FormExpr form_expr) -> SemIR::InstId {
   auto result_type_id = GetPatternType(context, form_expr.type_component_id);
+  auto result_type_inst_id = context.types().GetTypeInstId(result_type_id);
   auto result_id = HandleAction<SemIR::OutFormParamPatternAction>(
-      context, loc_id, form_expr.type_component_inst_id,
+      context, loc_id, result_type_inst_id,
       {.type_id = SemIR::InstType::TypeId, .form_id = form_expr.form_inst_id});
   return AddInst<SemIR::ReturnSlotPattern>(
       context, loc_id,
diff --git a/toolchain/check/testdata/basics/raw_sem_ir/bundle.carbon b/toolchain/check/testdata/basics/raw_sem_ir/bundle.carbon
index ac071035b358..3241dd05fac6 100644
--- a/toolchain/check/testdata/basics/raw_sem_ir/bundle.carbon
+++ b/toolchain/check/testdata/basics/raw_sem_ir/bundle.carbon
@@ -38,7 +38,7 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:     entity_name70000001: {name: name1, parent_scope: name_scope70000001, index: -1, is_template: 0, is_unused: 0, form: inst<none>}
 // CHECK:STDOUT:     entity_name70000002: {name: name1, parent_scope: name_scope<none>, index: 0, is_template: 0, is_unused: 0, form: inst<none>}
 // CHECK:STDOUT:   functions:
-// CHECK:STDOUT:     function70000000: {name: name0, parent_scope: name_scope0, call_param_patterns_id: inst_block70000007, call_params_id: inst_block70000008, return_type_inst_id: inst70000024, return_form_inst_id: inst70000021, return_pattern_id: inst7000002B}
+// CHECK:STDOUT:     function70000000: {name: name0, parent_scope: name_scope0, call_param_patterns_id: inst_block70000007, call_params_id: inst_block70000008, return_type_inst_id: inst70000024, return_form_inst_id: inst70000021, return_pattern_id: inst7000002C}
 // CHECK:STDOUT:   classes:         {}
 // CHECK:STDOUT:   interfaces:      {}
 // CHECK:STDOUT:   associated_constants: {}
@@ -113,33 +113,33 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:     inst70000024:    {kind: TypeComponentOf, arg0: inst70000022, type: type(TypeType)}
 // CHECK:STDOUT:     inst70000025:    {kind: PatternType, arg0: inst70000024, type: type(TypeType)}
 // CHECK:STDOUT:     inst70000026:    {kind: OutFormParamPatternAction, arg0: inst70000021, type: type(inst(InstType))}
-// CHECK:STDOUT:     inst70000027:    {kind: SpliceInst, arg0: inst70000026, type: type(symbolic_constant7000000C)}
-// CHECK:STDOUT:     inst70000028:    {kind: SpliceInst, arg0: inst70000026, type: type(symbolic_constant70000008)}
+// CHECK:STDOUT:     inst70000027:    {kind: SpliceInst, arg0: inst70000026, type: type(symbolic_constant7000000D)}
+// CHECK:STDOUT:     inst70000028:    {kind: SpliceInst, arg0: inst70000026, type: type(symbolic_constant70000009)}
 // CHECK:STDOUT:     inst70000029:    {kind: TypeComponentOf, arg0: inst70000023, type: type(TypeType)}
-// CHECK:STDOUT:     inst7000002A:    {kind: SpliceInst, arg0: inst70000026, type: type(symbolic_constant7000000C)}
-// CHECK:STDOUT:     inst7000002B:    {kind: ReturnSlotPattern, arg0: inst70000027, arg1: inst70000024, type: type(symbolic_constant7000000F)}
-// CHECK:STDOUT:     inst7000002C:    {kind: ReturnSlotPattern, arg0: inst70000028, arg1: inst70000024, type: type(symbolic_constant70000009)}
-// CHECK:STDOUT:     inst7000002D:    {kind: PatternType, arg0: inst70000029, type: type(TypeType)}
-// CHECK:STDOUT:     inst7000002E:    {kind: ReturnSlotPattern, arg0: inst7000002A, arg1: inst70000029, type: type(symbolic_constant7000000F)}
+// CHECK:STDOUT:     inst7000002A:    {kind: PatternType, arg0: inst70000029, type: type(TypeType)}
+// CHECK:STDOUT:     inst7000002B:    {kind: SpliceInst, arg0: inst70000026, type: type(symbolic_constant7000000D)}
+// CHECK:STDOUT:     inst7000002C:    {kind: ReturnSlotPattern, arg0: inst70000027, arg1: inst70000024, type: type(symbolic_constant7000000D)}
+// CHECK:STDOUT:     inst7000002D:    {kind: ReturnSlotPattern, arg0: inst70000028, arg1: inst70000024, type: type(symbolic_constant70000009)}
+// CHECK:STDOUT:     inst7000002E:    {kind: ReturnSlotPattern, arg0: inst7000002B, arg1: inst70000029, type: type(symbolic_constant7000000D)}
 // CHECK:STDOUT:     inst7000002F:    {kind: SpliceBlock, arg0: inst_block70000005, arg1: inst70000017, type: type(TypeType)}
 // CHECK:STDOUT:     inst70000030:    {kind: CalleePatternMatchAction, arg0: bundle70000000, type: type(inst(InstType))}
-// CHECK:STDOUT:     inst70000031:    {kind: SpliceInst, arg0: inst70000030, type: type(symbolic_constant7000000C)}
+// CHECK:STDOUT:     inst70000031:    {kind: SpliceInst, arg0: inst70000030, type: type(symbolic_constant7000000D)}
 // CHECK:STDOUT:     inst70000032:    {kind: ReturnSlot, arg0: inst70000024, arg1: inst70000031, type: type(symbolic_constant7000000C)}
 // CHECK:STDOUT:     inst70000033:    {kind: FunctionDecl, arg0: function70000000, arg1: inst_block7000000A, type: type(inst7000003C)}
 // CHECK:STDOUT:     inst70000034:    {kind: RefineFormAction, arg0: inst7000001D, type: type(inst(InstType))}
 // CHECK:STDOUT:     inst70000035:    {kind: SpliceInst, arg0: inst70000034, type: type(inst(FormType))}
 // CHECK:STDOUT:     inst70000036:    {kind: OutFormParamPatternAction, arg0: inst70000035, type: type(inst(InstType))}
 // CHECK:STDOUT:     inst70000037:    {kind: TypeComponentOf, arg0: inst70000035, type: type(TypeType)}
-// CHECK:STDOUT:     inst70000038:    {kind: SpliceInst, arg0: inst70000036, type: type(symbolic_constant70000015)}
-// CHECK:STDOUT:     inst70000039:    {kind: PatternType, arg0: inst70000037, type: type(TypeType)}
-// CHECK:STDOUT:     inst7000003A:    {kind: ReturnSlotPattern, arg0: inst70000038, arg1: inst70000037, type: type(symbolic_constant70000017)}
+// CHECK:STDOUT:     inst70000038:    {kind: PatternType, arg0: inst70000037, type: type(TypeType)}
+// CHECK:STDOUT:     inst70000039:    {kind: SpliceInst, arg0: inst70000036, type: type(symbolic_constant70000016)}
+// CHECK:STDOUT:     inst7000003A:    {kind: ReturnSlotPattern, arg0: inst70000039, arg1: inst70000037, type: type(symbolic_constant70000016)}
 // CHECK:STDOUT:     inst7000003B:    {kind: CalleePatternMatchAction, arg0: bundle70000001, type: type(inst(InstType))}
 // CHECK:STDOUT:     inst7000003C:    {kind: FunctionType, arg0: function70000000, arg1: specific<none>, type: type(TypeType)}
 // CHECK:STDOUT:     inst7000003D:    {kind: TupleType, arg0: inst_block_empty, type: type(TypeType)}
 // CHECK:STDOUT:     inst7000003E:    {kind: StructValue, arg0: inst_block_empty, type: type(inst7000003C)}
 // CHECK:STDOUT:   bundles:
 // CHECK:STDOUT:     bundle70000000:  {arg0: inst70000027, arg1: call_param0}
-// CHECK:STDOUT:     bundle70000001:  {arg0: inst70000038, arg1: call_param0}
+// CHECK:STDOUT:     bundle70000001:  {arg0: inst70000039, arg1: call_param0}
 // CHECK:STDOUT:   constant_values:
 // CHECK:STDOUT:     values:
 // CHECK:STDOUT:       instF:           concrete_constant(instF)
@@ -165,12 +165,12 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:       inst70000024:    symbolic_constant70000008
 // CHECK:STDOUT:       inst70000025:    symbolic_constant70000009
 // CHECK:STDOUT:       inst70000026:    symbolic_constant7000000A
-// CHECK:STDOUT:       inst70000027:    symbolic_constant7000000D
+// CHECK:STDOUT:       inst70000027:    symbolic_constant7000000E
 // CHECK:STDOUT:       inst70000028:    symbolic_constant7000000B
 // CHECK:STDOUT:       inst70000029:    symbolic_constant7000000C
 // CHECK:STDOUT:       inst7000002A:    symbolic_constant7000000D
-// CHECK:STDOUT:       inst7000002B:    symbolic_constant70000010
-// CHECK:STDOUT:       inst7000002C:    symbolic_constant7000000E
+// CHECK:STDOUT:       inst7000002B:    symbolic_constant7000000E
+// CHECK:STDOUT:       inst7000002C:    symbolic_constant70000010
 // CHECK:STDOUT:       inst7000002D:    symbolic_constant7000000F
 // CHECK:STDOUT:       inst7000002E:    symbolic_constant70000010
 // CHECK:STDOUT:       inst7000002F:    concrete_constant(inst(FormType))
@@ -201,10 +201,10 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:       symbolic_constant7000000A: {inst: inst70000026, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl4}}
 // CHECK:STDOUT:       symbolic_constant7000000B: {inst: inst70000028, kind: template, attached: null}
 // CHECK:STDOUT:       symbolic_constant7000000C: {inst: inst70000024, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl5}}
-// CHECK:STDOUT:       symbolic_constant7000000D: {inst: inst70000028, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl6}}
-// CHECK:STDOUT:       symbolic_constant7000000E: {inst: inst7000002C, kind: template, attached: null}
-// CHECK:STDOUT:       symbolic_constant7000000F: {inst: inst70000025, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl7}}
-// CHECK:STDOUT:       symbolic_constant70000010: {inst: inst7000002C, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl8}}
+// CHECK:STDOUT:       symbolic_constant7000000D: {inst: inst70000025, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl6}}
+// CHECK:STDOUT:       symbolic_constant7000000E: {inst: inst70000028, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl7}}
+// CHECK:STDOUT:       symbolic_constant7000000F: {inst: inst7000002D, kind: template, attached: null}
+// CHECK:STDOUT:       symbolic_constant70000010: {inst: inst7000002D, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl8}}
 // CHECK:STDOUT:       symbolic_constant70000011: {inst: inst70000030, kind: template, attached: {generic: generic70000000, index: generic_inst_in_decl9}}
 // CHECK:STDOUT:       symbolic_constant70000012: {inst: inst70000034, kind: template, attached: null}
 // CHECK:STDOUT:       symbolic_constant70000013: {inst: inst70000035, kind: template, attached: null}
@@ -235,7 +235,7 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:       0:               inst70000031
 // CHECK:STDOUT:     inst_block70000009:
 // CHECK:STDOUT:       0:               inst70000019
-// CHECK:STDOUT:       1:               inst7000002B
+// CHECK:STDOUT:       1:               inst7000002C
 // CHECK:STDOUT:     inst_block7000000A:
 // CHECK:STDOUT:       0:               inst7000001F
 // CHECK:STDOUT:       1:               inst70000021
@@ -256,7 +256,7 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:       4:               inst70000026
 // CHECK:STDOUT:       5:               inst70000029
 // CHECK:STDOUT:       6:               inst7000002A
-// CHECK:STDOUT:       7:               inst7000002D
+// CHECK:STDOUT:       7:               inst7000002B
 // CHECK:STDOUT:       8:               inst7000002E
 // CHECK:STDOUT:       9:               inst70000030
 // CHECK:STDOUT:     inst_block7000000E:
diff --git a/toolchain/check/testdata/function/call/form.carbon b/toolchain/check/testdata/function/call/form.carbon
index f72f60401310..37c75d3ba4c4 100644
--- a/toolchain/check/testdata/function/call/form.carbon
+++ b/toolchain/check/testdata/function/call/form.carbon
@@ -569,16 +569,16 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:   %.344: Core.Form = splice_inst @F.%.loc4_28.1 [template]
 // CHECK:STDOUT:   %.82f: type = type_component_of %.344 [template]
 // CHECK:STDOUT:   %pattern_type.ec7: type = pattern_type %.82f [template]
-// CHECK:STDOUT:   %.f74: %.82f = splice_inst @F.%.loc4_24.2 [template]
-// CHECK:STDOUT:   %return.patt.08d: %pattern_type.ec7 = return_slot_pattern %.f74, %.82f [template]
+// CHECK:STDOUT:   %.b9b: %pattern_type.ec7 = splice_inst @F.%.loc4_24.2 [template]
+// CHECK:STDOUT:   %return.patt.96f: %pattern_type.ec7 = return_slot_pattern %.b9b, %.82f [template]
 // CHECK:STDOUT:   %.33d: <instruction> = refine_form_action %Form [template]
 // CHECK:STDOUT:   %.80a: Core.Form = splice_inst %.33d [template]
 // CHECK:STDOUT:   %.af3: <instruction> = out_form_param_pattern_action %.80a [template]
 // CHECK:STDOUT:   %.465: type = type_component_of %.80a [template]
-// CHECK:STDOUT:   %.e7f: %.465 = splice_inst %.af3 [template]
 // CHECK:STDOUT:   %pattern_type.a51: type = pattern_type %.465 [template]
-// CHECK:STDOUT:   %return.patt.de8: %pattern_type.a51 = return_slot_pattern %.e7f, %.465 [template]
-// CHECK:STDOUT:   %.cab: <instruction> = callee_pattern_match_action %.e7f, call_param0 [template]
+// CHECK:STDOUT:   %.3c2: %pattern_type.a51 = splice_inst %.af3 [template]
+// CHECK:STDOUT:   %return.patt.de0: %pattern_type.a51 = return_slot_pattern %.3c2, %.465 [template]
+// CHECK:STDOUT:   %.849: <instruction> = callee_pattern_match_action %.3c2, call_param0 [template]
 // CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -595,18 +595,18 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %Form.patt.loc4_10.1: %pattern_type.13f = symbolic_binding_pattern Form, 0 [symbolic = %Form.patt.loc4_10.2 (constants.%Form.patt)]
-// CHECK:STDOUT:     %return.patt.loc4_24.1: @F.%pattern_type (%pattern_type.ec7) = return_slot_pattern %.loc4_24.6, constants.%.82f [template = %return.patt.loc4_24.2 (constants.%return.patt.08d)]
+// CHECK:STDOUT:     %return.patt.loc4_24.1: @F.%pattern_type (%pattern_type.ec7) = return_slot_pattern %.loc4_24.6, constants.%.82f [template = %return.patt.loc4_24.2 (constants.%return.patt.96f)]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %Form.ref.loc4_28: Core.Form = name_ref Form, %Form.loc4_10.2 [symbolic = %Form.loc4_10.1 (constants.%Form)]
 // CHECK:STDOUT:     %.loc4_28.3: Core.Form = splice_inst %.loc4_28.1 [template = %.loc4_28.2 (constants.%.344)]
-// CHECK:STDOUT:     %.loc4_24.6: @F.%.loc4_24.3 (%.82f) = splice_inst %.loc4_24.2 [template = %.loc4_24.4 (constants.%.f74)]
+// CHECK:STDOUT:     %.loc4_24.6: @F.%pattern_type (%pattern_type.ec7) = splice_inst %.loc4_24.2 [template = %.loc4_24.4 (constants.%.b9b)]
 // CHECK:STDOUT:     %.loc4_17: type = splice_block %Form.ref.loc4_17 [concrete = Core.Form] {
 // CHECK:STDOUT:       %.Self: %type = symbolic_binding .Self [symbolic_self = constants.%.Self]
 // CHECK:STDOUT:       %Core.ref: <namespace> = name_ref Core, imports.%Core [concrete = imports.%Core]
 // CHECK:STDOUT:       %Form.ref.loc4_17: type = name_ref Form, imports.%Core.Form [concrete = Core.Form]
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %Form.loc4_10.2: Core.Form = symbolic_binding Form, 0 [symbolic = %Form.loc4_10.1 (constants.%Form)]
-// CHECK:STDOUT:     %.loc4_24.1: @F.%.loc4_24.3 (%.82f) = splice_inst %.loc4_24.5
+// CHECK:STDOUT:     %.loc4_24.1: @F.%pattern_type (%pattern_type.ec7) = splice_inst %.loc4_24.5
 // CHECK:STDOUT:     %return: @F.%.loc4_24.3 (%.82f) = return_slot %.loc4_24.1
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -618,9 +618,9 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:   %.loc4_28.2: Core.Form = splice_inst %.loc4_28.1 [template = %.loc4_28.2 (constants.%.344)]
 // CHECK:STDOUT:   %.loc4_24.2: <instruction> = out_form_param_pattern_action %.loc4_28.3 [template]
 // CHECK:STDOUT:   %.loc4_24.3: type = type_component_of %.loc4_28.2 [template = %.loc4_24.3 (constants.%.82f)]
-// CHECK:STDOUT:   %.loc4_24.4: @F.%.loc4_24.3 (%.82f) = splice_inst %.loc4_24.2 [template = %.loc4_24.4 (constants.%.f74)]
 // CHECK:STDOUT:   %pattern_type: type = pattern_type %.loc4_24.3 [template = %pattern_type (constants.%pattern_type.ec7)]
-// CHECK:STDOUT:   %return.patt.loc4_24.2: @F.%pattern_type (%pattern_type.ec7) = return_slot_pattern %.loc4_24.4, %.loc4_24.3 [template = %return.patt.loc4_24.2 (constants.%return.patt.08d)]
+// CHECK:STDOUT:   %.loc4_24.4: @F.%pattern_type (%pattern_type.ec7) = splice_inst %.loc4_24.2 [template = %.loc4_24.4 (constants.%.b9b)]
+// CHECK:STDOUT:   %return.patt.loc4_24.2: @F.%pattern_type (%pattern_type.ec7) = return_slot_pattern %.loc4_24.4, %.loc4_24.3 [template = %return.patt.loc4_24.2 (constants.%return.patt.96f)]
 // CHECK:STDOUT:   %.loc4_24.5: <instruction> = callee_pattern_match_action %.loc4_24.6, call_param0 [template]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn() -> out %.loc4_24.1:? @F.%.loc4_28.1 (@F.%.loc4_28.1);
@@ -633,9 +633,9 @@ fn F(Form:! Core.Form) ->? Form;
 // CHECK:STDOUT:   %.loc4_28.2 => constants.%.80a
 // CHECK:STDOUT:   %.loc4_24.2 => constants.%.af3
 // CHECK:STDOUT:   %.loc4_24.3 => constants.%.465
-// CHECK:STDOUT:   %.loc4_24.4 => constants.%.e7f
 // CHECK:STDOUT:   %pattern_type => constants.%pattern_type.a51
-// CHECK:STDOUT:   %return.patt.loc4_24.2 => constants.%return.patt.de8
-// CHECK:STDOUT:   %.loc4_24.5 => constants.%.cab
+// CHECK:STDOUT:   %.loc4_24.4 => constants.%.3c2
+// CHECK:STDOUT:   %return.patt.loc4_24.2 => constants.%return.patt.de0
+// CHECK:STDOUT:   %.loc4_24.5 => constants.%.849
 // CHECK:STDOUT: }
 // CHECK:STDOUT: